Linux Twin Stick Shooter sound does not have constant tempo

The firing sound in the Twin Stick Shooter template on the Linux machine does not have a constant tempo. The firing sound changes between evenly spaced sounds and closely spaced sounds.

I do not see this issue on Windows or HTML5.

REGRESSION: No
This issue also occurs in [4.9] GITHUB PROMOTED build UE4-Releases/4.9/Promoted-CL-2707645

1. Open UE4Editor
2. Create a new Twin Stick Shooter BP project
3. PIE
4. Hold down the Up arrow to fire constantly

RESULT:
The firing sound does not have a constant speed